There are currently two schemes for structuring an infrared focal plane array, namely the monolithic and the hybrid approaches. The monolithics are being developed both as extrinsics, where well established silicon batch processing technology can be exploited, and as intrinsics in the Groups III-V, II-VI, and IV-VI trimetal alloys. The incentives for developing monolithic intrinsic arrays in these trimetal alloy systems are the well-known advantages of high operating temperature, low cross talk, and high quantum efficiency. The hybrid approach couples two independent and relatively mature technologies; namely, intrinsic alloy photovoltaic arrays and silicon CCD multiplexers. Advantages of this approach include the ability to independently select and optimize the detector and readout media. The benefits however must be considered in light of the very difficult requirement for an advanced high yield physical and electrical interconnect technology which severely limits the detector density and device reliability, which is caused by the nature of the detector/multiplexer interface.
An ideal focal plane array, which includes sensor (dectector) signal processor, multiplexer, and interface electronics, would be a monolithic intrinsic structure capable of being tuned for operation over the spectral region of interest, i.e. 0.8-14 microns, and whose construction is simple and compatible with large scale integration techniques. It is also desirable that the array be radiation hard, unscanned, and capable of being operated at higher practical temperatures than is needed for extrinsic silicon. The present invention comprises the concept, operation, and method of fabrication of such a focal plane array.